Art or process of liquefying air and separating the same into oxygen and nitrogen.



' J. F. PLACE.

ART 0R PROCESS OF LIQUEFYLNG AIR AND SEPARATING THE SAME INTO OXYGEN ANDNITROGEN.

I APPLICATION FILED NOV.L3,l911- LLWKQQ. Patented Oct. 26,1915.

J. F. PLACE.

ART 0N PROCESS OF LIOUEFYING AIR AND SEPARATING THE SAME INTO OXYGEN ANDNITROGEN.

APPLICATION FILED NOV- I3, 91!.

9 if. a

Patented 001:. 26, 1915.

2 SHEEIS SHEET 2.

In ven 1:01:

JAMES F. PLACE, OF GLEN RIDGE, NEW LIQUEFYING COMPANY, OF NEW YORK,

JERSEY, ASSIGNOB T ERIOAN AIR N. COBPOATI ON OF NEW YORK.

ART 0R PROCESS OF LIQUEFYING AI ER AND SEPARATING THE SAME INTO OXYGENAND NITROGEN.

Specification of Letters Patent.

Patented Uct, fit, 1915.

Apphcation sued. November 13,1911. serial no. acacia To all whom it mayconcern:

Be it known that I, JAMns F. PLAoE, a

' citizen of the United States, and resident of in the cost ofproduction of oxygen and ni- Glen Ridge, in the county of Essex andState of New Jersey, have invented certain new and useful Improvementsin the Art or Process of Liquefying the Same into Oxygen and Nitrogen,of which the following is a specification.

My invention relates to improvements in the art or process ofliquefyingair and of separating the same into its constituentparts-oxygen and nitrogen; and its prin-' cipal object is to simplifythe process with an accompanying increase in the efficiency of operationand at the same time a decrease trogen and also an increase in theirpurlty.

To these and other ends,. as will appear from the detailed descriptionwhich follows, my invention comprehends and consists of the features orsteps fully described and explained in connection with the drawin s, to

. which reference should be had for a ful and complete. understanding ofthe same, the said invention being particularly pointed out in theclaims.

In order that those skilled in the art may understand and make use of myinvention 1 will describe my improved process, by help of theaccompanying drawings, by which it may be operated, and in which- Figure1 shows in section, a complete apparatus whereby the process may beavailed of. Fig. 2 is a view in diagrammatic form, partly in verticalsection and partly in elevation, of that portion of the above apparatusdevoted spe-- cially to the separation of the oxygen and nitrogen ofair, in a modified form. Figs. 3 and a are views on a larger scale ofthe cone-coil and its radiallygrooved deflector the first in elevation,and the second a top view plan of the deflector only,- forming a part ofthe separating apparatus.

Similar reference marks refer to similar parts through the severaldrawings.

lln Fig. 1 of the drawings at 1 and 1 ll show ordinary air compressors,to supply the liquefier and the air expansion engine 2; at 1 is shownthe'air compressor to supply air of low compression to the rectifier.All of these compressors are driven from an Air and Separating 'dioxidfrom the air.

diagrammatic form partly in elevation and partly in vertical" outsidesource of power, not shown in the drawlngs. At 3 is shown the liquefyingcoils of the primary liquefier, inclosed in the casing 4, and in thesame casing I show also the cooling coil 15, for cooling the air supphedto the air expandin engine 2-- both of which are supplie with compressedair from the freezing drum 5, when only one compressor is used (either 1or 1 to suppl both the liquefier and expansion engine. At 6 and 6' Ihave respectively a calcium chlerid drum and a caustic potash drum, forremoving moisture and carbon At 7 I havea highpressure liquid air tankor container, for taking he liquefied air as produced in the hquefyingcoils 3, as it falls by gravity through the connecting pipe 8; and at 91 show a low-pressure li uid air holder. The liquid in the container isunder same compression as when liquefied, and is partially released frompressure by the releasing valve 10, and is delivered to the holder 9through the siphon tube 11; the pressure in the casing t and holder 9 ismaintained at a few pounds only-just enough to force the liquid up intothe rectifying column 12 through the siphon 13 and discharge pipe 14;.vi hen the liquid is released from the container 7 and delivered to theholder 9, the container '7 becomes submerged in the released liquid insaid holder, which subcoolsany further liquid under pressure in saidcontainer; and any of the liquid which evaporates when released orpartially released from pressure through valve 10, goes up through thecasing 1 and helps cool or liquefy' the incoming compressed air.

v The expansion engine 2 is supplied with compressed air, which has beencooled in the interchanger coils 15, through the feed pipe 16; inord'erto easily regulate the initial temperature of this air to beexpanded in the engine, 1 have a cut-out conduit 17, from the casing 1to the return flow conduit 18, through the valve 19; any of the cold 6X-paneled air which is passed through this cutout conduit goes direct intothe freezing coil 20 in the freezing drum 5, and therefore the airsupplied to the engine through the interchanger 15 is not cooled to solow a temperature; to further regulate the temperature of this air to beexpanded, 1 have a feed pipe 21, so that some of the unliqueablymaintain the temperature of this initial compressed air supplied toengine 2, so that as it expands the temperature of the exhaust air isdown to its liquefying point, and thus the expanded air as it ascends inthe casing 4 around the liquefying coils 3,

and in thermal contact with and in countercurrent to the air. suppliedto and being cooled and liquefied therein, it is so much colder than theliquefaction temperature of the air in said liquefying coils, that thecompressed air therein readily becomes liquefied, and the liquid dripsdown through pipe 8 and is collected below in the high-pressurecontainer 7. For, in the operation of my process, the lower the pressurewhich can be maintained in the liquefying coils 3 to permit ofsuccessful working, the greater is the efiiciency.

- The operation of that part of the appa ratus devoted to theliquefaction of air or other gaseous mixtures, is as follows: When twopressures are used, the air to be expanded in the air-expansion engineis compressed in compressor 1, being drawn in through the suction checkvalve 24, and after compression it is water-cooled and sent throughvalves 25 and 44 (valves 26 and 27 being closed.) thence it passesthrough the calcium chlorid drum 6,and much of the moisture thereinbeing absorbed, it is conducted through pipe 28, to the caustic potashdrum 6 wherein the carbon dioxid in the air is removed, and from thenceit passes through pipe 29 and valve 30 into the freezing drum 5, whereinall of the remaining moisture in the air is frozen out, and gathers asfrost on the outside surfaces of the low pressure metal conduit 20-thecold expanded air in the conduit 20 being arranged to pass downwardlythrough the conduit, and the compressed air in the drum 5 passingupwardly in counter-current thereto.

lhe compressed air to be expanded is then sent through the connectingpipe 31 and valve 32, into the cooling coils 15 through valve 33 andpipe 34, the valve 35 being closed; in the cooling coils 15, it passesdownwardly in a contrary direction to the cold expanded air and vaporspassing up through the casing 4, and being properly cooled therein bythermal but not physical contact with said ascending cold expanded gasesand vapors it is delivered through pipe 16 to engine 2, wherein it issuitably expanded, and the cold exhaust expanded gases are thendelivered through conduit 23 to the casing 4, just below the liquefyingcoils 3; thence these cold expanded gases pass through the conduit 18and freezing coils 20 to the return conduit 36, and are thence deliveredto the compressor 1, 'and recompressed, the same air being used over andover again. The engine 2 is belted to the compressor 1 as Shown at37 andthe work thereof is recovered in helping to compress the air used.

.Afterthe apparatus is roperly cooled the drums 6 and 6' and freezingdrum 5 are cut out from the circuit, by closing valves 25 and 32, andopening valves 27, valve 33 being already open, when the compressed airnow thoroughly dry and free from C0, gas is made to pass through thecut-out pipe 38 and valve 33 direct to the counter-currentcooling coils15. The other compressor 1, for supplying air of higher tension, to theliquefier, may then be started up, drawing air in through the suctionpipe-39 and check valve 40valve 41 (which: connects the suction pipes ofthe two compressors) being closed. This higher-pressure air is thendelivered through discharge pipe 42 and valves 26 and 44 to thehydroscopic drums 6 and 6, and the freezing drum 5, thence through valve35 (valves 32 and 25 being closed, and valve 30 opened.) through supplypipe 43 to the high-pressure liquefying coils 3, wherein it is liquefiedby the cold expanded gases from the engine exhaust conduit 23, and dripsby gravity through connecting pipe 8 into the container 7.

By closing valves 44, 30, 35 and 33, and opening valves 25, 27, and 32,and drip cook 45, hot air from the compressor 1 may be sent through thefreezing drum 5, and the frost on the conduit 20 melted and drained outthrough the drip cock 45. At 46 I have a relief valve, to allow anysurplus gas in conduit 36 to escape, and set so as to force a suitableback-pressure in the casing 4; and at 47 I have a pressure-releasingvalve, whereby some of the unliquefied gases from the liquefying coils 3may be released to the casing 4 to go back over and help cool andliquefy the incoming compressed air in said liquefying coils, ifdesired. Ordinarily this valve is not used.

When onlv one pressure is desired to supply both the expansion engineand the lique fier, preferably compressor 1 is used, and valves 26, 30,32, 33, 35, 41 and 44 are opened, and valves 25 and 27 are closed; allof the compressed air is then passed through the drums 6 and 6', and thefreezing drum 5, and is delivered one portion through valve 33 to thecooling coils 15 to be expanded, and the other portion through valve 35to the liquefying coils 3 to be liquefied. When only compressor 1 isused, the engine should he made to do work on that compressor, by beltas shown at 48.

Having produced the liquid air and released the same to the low-pressureholder 9 it is then delivered to the top of the rectifying column 12through siphon 18, valve 49 and pipe 14 and the spray head 50; fromthence it falls and drips down the column 12 through the pebbles orglass balls (36 The rectifying apparatus consists of the followingparts: At 1 is the low-pressure compressing the air to a suitabletension, ordinarily not over one to three atmospheres; and at 51 and 52l have the moisture and CO, gas extracting drums, respectively, similarto the drums (3 and ti, and at 53 I show a low-pressure freezing drum,also similar to that used in the liquefying process. [it 54 l. have acounter-current cooling casing, with the cooling coil 55 inclosedtherein to cool the low-tension compressed air being conductedtherethro'ugh (in a contrary direction to the return flow of coldexpanded air in the casing 54), to he used in the rectifying process;the cold pipe 56 (containing air about to he liquefied) is preferablyinsulated as shown at 57, The air of light compression from thecompressor 1, is first cooled and then passed through dis charge pipeEll and -valve 92 to the hydroscopic drums 51 and 52, and thence throughpipe 89 and valve 93 to the freezing drum 53, and thence through valve90 to the intercluinger coils 55, Within the rectifying column 12, lhave my improved cone-coil liquefier 58, which is more clearly shown inFig. 3, surmounted by my improved radially grooved rectifying deflector59. And at 68 is shown my improved liquid holding and separatingcontainer, which is wholly or in part submerged in the released oxygenliquid in holder 81. Cold pipe 56 is connected with and delivers to thecone-coil liqu'efier, pref erahly to the upper coil thereof as shown,and throughvalve (32. The liquid obtained in the cone liquefier, ascollected in the container 80 through discharge pipe 77 is di chargedthrough the siphon pipe 63 through valve 64: and the spray-head 65; itthen Iningles with the descending liquid air discharged from thespray-head 50, higher up,

and drips down through the pebbles or balls- 86 on to the deflector 59,and over the outer surfaces of the helical coils on the inside or withinthe hollow cone of the cone-coil liquei er 58, and finally is collectedin the holder 61l1aving in its fall from the head 65 become rectified topractically pure oxygen liquid, the nitrogen gas passing ofi' through.conduit 67 to the cooling interchanger 54, and down through the freezingcoil 68 and up through the conduit 69 and'down around he7drums 52 and51,-and through the out-, et 0..

The liquid oxygen collected in the holder 61, may be drawn out throughthe siphon tube 71 and valve 72 and delivery cock 78; or it may bedelivered through the valve 7 1- and tube 75 to the oxygen vaporizingreservoir 78. The liquid obtained in the con tainer 60 is separated fromthe unliquefied gaseous residue in the top of said container, bothliquefied and unli uefied being delivered from the lique ying cone coilsthrough the connecting pipe 77. From here the unliquefied gaseousresidue may he sent through valve 78 and pipe 80 to the liquefying coil79 in the reservoir 76, where it is liquefied by giving up heat inevaporating the oxygen 11 uid in said reservoir, and as liquefied it isorced up through pipe 8land valve 81' into pipe l t and is mixed withthe liquid air therein from holder 9 and delivered therewith throughspray-head 50 to the top of the rectifying column 12, to be rectified asit falls down through the column. The oxygen liquid in reservoir 7811sthereby evaporated and the practically pure oxygen gas passes up throughconduit 82 into the drum 83 where it turther cools the compressed air inthe coil pipe 84 therein and such cool air passes down through pipe 85into the cone-coil liquefier 58 as shown. The oxygen gas may then hecollected from the outlet cook 88. The coil 84: is supplied with cooledand dry compressed air through valve 87 and connecting pipe 88, which isfed. from the primary interchanger cooling coils 55. The moisture frozenout from the air in drum 58, may he removed by closing valves 98, 92 and93 and opening valve 94 and drip cook 95, and passing warm or hot airfrom the compressor through the Toy-pass 98 to the freezing drum 53.

At 97 l have a valve connecting pipe 8O through valve 98 with the pipe99 which delivers to the nitrogen escape conduit 67, so that portions ofthe unliquefied gaseous residue as separated from the liquid 1ncontainer 60, may he sent direct to the interchanger drum 54-, ifdesired, or when the oxygen liquid is drawn of]? from. outlet 73, andnot vaporized in the vaporizing reservoir "[6. Some of this coldunliquefied gaseous residue may he passed through valve 100 direct intothe freezing coil 68, if desired. The drums 51 and 52 are inclosed in aninsulating case 101, and are each provided with a drip cock 102 and 103.I also provide a check valve 10% in the nitrogen. rethnn flow conduit67, so as to maintain a slight backpressure in the rectifying columnandholder til; and by having the outlet valve 105, liquid air beforerectification may he drawn out from the holder 9 through siphon tube 13,if desired.

in Fig. 2 l have illustrated a modlfied construction of that portion ofthe apparatus employed by me in the carrying out o lltlid lllld myprocess for the purpose of cooling and liquefying the air under lowcompression and rectifying the same. In the said modified construction1, as in Fig. 1, designates a compressor in which the air is placedunder a low degree of pressure or compression and from which it isconducted through the pipeOl and valve 92 into and through the drums 51'and 52, which are similar to the drums 6 and 6' in Fig. 1, and which areprovided with means for extracting the moisture and CO, from the air.From the drum 52 the air is conducted through the pipe 89 and valve 93into the low pressure freezing drum 53. From this drum the air isconveyed through coiled pipe 55' which is situated within the casin 5%.The pipe 55' consists of the coiled portion and a straight portionextending through such coiled portion, the said straight and coiledportions being separated from each other by means of a casing ofinsulation 57' which surrounds the straight portion of .the pipe. Thestraight portion of the. pipe is extended as indicated at56 and ispreferably connected, as shown, to the upper part of the liquefying coil58 in which liquefaction in part or in whole of the air is effected byreason of the fact that it is subjected to the action of the coldrectified liquid from the rectifyingcolumn 66'. p

The liquefied gas, aswell as any portion thereof which is not liquefied,is delivered from the coil 58 through pipe 77to thereceiver 60. Fromthis receiver the liquefied portion of the air passes out through thepipe or tube 63', the valve 64 being opened to permit such outwardpassage, and is discharged therefrom through the nozzle 65 which islocated in the rectifying column (36. The liquid thus discharged mixesand intermingles with the downwardly flowing liquid which has beendischarged from the nozzle 50' as the liquid flows downward through thepebbles or glass balls 66*" in the rectifying column. The nitrogen beingthe more volatile is separated from the oxygen in the rectifying columnand passes from such column through the pipe 67 and enters the casing ordrum 54 moving downwardly therein, surrounding the cooling pipe 55. Fromthe casing 54' the cooled gas passes out through the pipe communicatingtherewith and passes thence into the coiled pipe 68 in the low pressurefreezing chamber 53' from which it passes through the pipe 69' into thecasing 101 through which it travels, surrounding the drums 52' and 51',finally escaping through the discharge opening 70.

It will thus be seen that the air under low compression which isforwarded from the compressor 1 is caused to flow in a directionopposite to that of the flow of the cold gases so. that it is therebyrendered very cold moved therefrom through a pipe 71 and valve 72' inthe same manner as described in connection with the container (31 andparts 71and 72 in Fig. 1 of the drawings; or instead of passing outthrough the valve 78 the latter may be closed and the valve 98 opened,the valve 100 being closed so that the unliquefied portion of the air orgas is conducted through the pipe 99 which delivers the same into thepipe (37; or instead of passing such unliquefied portion of the airthrough the valve 98 the latter may be closed and the valve 100' openedin which case the said unliquefied portion will travel toward the rightthrough the coil pipe 68 as previously described in connection with thegas escaping. through the pipe (37 from the rectifying column (36.

95' designates a drip cock from the low pressure freezing drum 53.

102 and 103 designate drip cocks from the drums 51' and 52. I

The moisture frozen out from the air in drum 53' may be removed byclosing valves 90, 92 and 93 and opening valve 94,, drip cock 95' andpassing warm air from the compressor through the by-pass 96 to thefreezing drum 53'.

All parts of the apparatus having a temperature below normal when inoperation, are thoroughly insulated with suitable materials of lowthermal conductivity.

Having thus described my invention, what I claim as new and original anddesire to secure by Letters Patent, is

1. The process of liquefying atmospheric air, which consists incompressing the air, cooling the same, and liquefying a part of oneportion thereof and expanding with production of recoverable externalwork the unliquefied gaseous residue of such portion along with theother portion; and finally partially releasing from pressure the liquidthus obtained and sub-cooling therewith the unreleased liquid.

2. The process of liquefying atmospheric air, which consists incompressing the air,

cooling the same, and expanding a portion thereof with production ofrecoverable external work, and then liquefying under pressure a part ofthe other portion by the combined refrigerative effect of the coldexpanded portion and the unliquefied gases of the other portion; andfinally partially releasing from pressure portions of the liquid thusobtatined and sub-cooling therewith the urn released portions thereof.

3. The process-of liquefying atmospheric air, which consists incompressing the air,

memes I cooling the same, and liquefying a part of one portion thereofandexpanding with production of recoverable external work theunliquefied gaseous residue of such portion alon with the other portion;and finally partially releasing from pressure portions of the liquidthus obtained and sub-cooling therewith the unreleased portions thereof.

4. The process of liquefying atmospheric air which consists incompressing portions of air, cooling the same and liquefying a part ofone of said portions and expanding the unliquefied gaseous residue ofsuch portion along with the other of said portions and finall partiallyreleasing from pressure the liquefied gases of the air thus obtained andutilizing the cold vapors from such as evaporate upon said release tocool the incoming supply of compressed air. 7

5. The process of liquefying atmospheric air which consists incompressing portions of air, coolin the same, and liquefy-ing a part ofone 0 said portions and expanding 4 with production of recoverableexternal work the unliquefied gaseous residue of such portion along withthe other of said por- I tions and finally partially releasing frompressure the liquefied gases of the air thus obtained and utilizing thecold vapors from such as evaporate upon said release to cool theincoming supply of compressed air.

6. The process of liquefying atmospheric air which consists incompressing portions of air, cooling the same and expanding one of saidportions and then liquefying under pressure a part of the other portionby the combined refrigerative eliect of the cold expanded portion andthe unliquefied part of the said other portion and finally partiallyreleasing from pressure the liquid thus obtained and sub-coolingtherewith the unreleased liquid,

Signed at New York city in the county of New York and State of New Yorkthis 8th day of, November A. D. 1911.

JAMES F. PLACE.

